A Short Guide to Hard Anodising

Well known as an excellent treatment for a diverse range of metals and materials, anodisation is a cost-effective way to protect tools and parts from damage and corrosion. Suitable for items made of everything from aluminium through to certain plastics, it’s an extremely versatile process, and the finished result looks great too. Hard anodisation offers the very best that this treatment can provide and makes an excellent choice for many items.

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What Is Hard Anodising?

The process of anodisation takes place in a bath of an electrolyte liquid. The product to be anodised then acts as an anode when an electrical current is applied to the bath, releasing oxygen ions. These oxygen ions then bond with the metal’s surface, creating a hard oxide layer. For example, when the process is applied to aluminium items, a protective layer of aluminium oxide is created. The longer the electrical current is continued, the deeper and harder the layer of oxide protection becomes. When the protection extends to 25 microns and above, the result is classified as hard anodising. More information about the science behind the anodisation process can be found at

Sealant methods can be included in the treatment process through the addition of hot water, nickel acetate, tri-valent chromate or PTFE. This means that the finished result will demonstrate lipophobic and hydrophobic results – simply put, if oil or water comes into contact with the hard anodised item, the liquid will bead on the surface rather than be able to penetrate it. As a result, such sealing methods make the product extremely resilient to wear and corrosion. Therefore, when considering hard anodising PTFE or other sealants make a very worthwhile addition. Further information about sealing can be seen at

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The Benefits of Hard Anodising

There are many reasons why hard anodising is an excellent option. It particularly outperforms other processes such as sulphuric acid anodising, which can leave products less able to stand fatigue.

Hard anodising gives tools and parts a longer lifespan thanks to the increase in their ability to withstand wear. The use of sealants such of PTFE will further extend the wearability of hard anodised items. The coating makes the item much harder than the original surface, and this coating also protects the interior (also known as the substrate) from being exposed to water and other elements which could cause damage.

In tough, aggressive environments, products which have undergone hard anodisation are better able to resist corrosion, making it ideal for architectural elements or other exposed items. Hard anodised items can better resist extremes of temperature too, making it the ultimate protection for hard-working parts. The finished result can be attractive, with options for colouration available. Explore the many benefits and applications of hard anodising at

It’s clear that hard anodising is a superb choice. It’s the ideal defensive treatment for items exposed to the most challenging circumstances. Why not discover the benefits and try hard anodising for yourself?

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